1. Field of the Invention
This invention generally relates to hypodermic devices and, more particularly, is concerned with augmented polymeric hypodermic devices.
2. Description of the Prior Art
Metal hypodermic needles and lancets have not changed substantially in over 100 years. They have many disadvantages. The foremost is that they are dangerous. They are involved in the transmission of such deadly diseases as AIDS through inadvertent "needle sticks" of health care workers. Currently the risk is an unacceptable 1 in 200. In addition, the metal needles can break during use, requiring surgery to remove. Further, the metal needles and lancets are extremely difficult to destroy. Even segments or stubs of the needles and lancets are dangerous. They are not burnable by ordinary means and, thus, pose a continuing disposal and health problem.
Others have made many attempts to solve these problems. Their proposed solutions have taken two main routes. The first, is a substitution of plastic for metal in the needle material. The second, is a guard to shield the needle. Both avenues have failed for a variety of reasons. Plastic has not replaced metal because thin plastic needles that are hard enough to puncture the skin are too brittle and shatter, while more flexible needles lack the requisite stiffness to pierce the skin. Previous needle guards have proven to be either unwieldy, too costly, inconvenient to use or otherwise ineffective.
The following patents are included for reference as to the state of the prior art at the time of this application.
A plastic hypodermic needle that attempts to mimic the shape and function of a conventional metal needle is described by U.S. Pat. No. 2,512,568 to Saffir. U.S. Pat. No. 2,512,569 also to Saffir illustrates metal and other hard materials used only on the tip of the plastic needles to facilitate skin puncture, much as metal arrowheads are put on wooden shafts. U.S. Pat. No. 2,954,768 to Hamilton shows plastic needles with unusual piercing tip configurations. U.S. Pat. No. 3,831,814 to Butler shows another large plastic needle with unusual tip geometry. A plastic hypodermic needle with angled side portals is revealed by U.S. Pat. No. 4,838,877 to Massau.
A closed, triangular cross section, metal hypodermic needle is shown in U.S. Pat. No. 3,090,384 to Baldwin et al.
Spring biased shields for conventional metal needles are shown by the following U.S. Pat. Nos. 2,674,246 to Bower; 2,876,770 to White; 3,134,380 to Armao; 4,416,663 to Hall; 4,507,118 to Dent; 4,664,654 to Strauss; 4,795,432 to Karczmer; and 4,929,237 to Medway.
To guard conventional metal needles, hand operated shields which slide into different positions on the hypodermic syringe body are shown in U.S. Pat. Nos. 4,695,274 to Fox; and 4,702,738 to Spencer.
U.S. Pat. No. 3,884,230 to Wulff describes a conventional metal hypodermic needle mounted on a flexible sleeve and surrounded by a biased spring assembly for inoculating livestock.
A resilient foam rubber or plastic biased guard of a conventional metal needle is shown by U.S. Pat. No. 4,775,369 to Schwartz. U.S. Pat. No. 4,883,068 to Dechow illustrates a blood sampling device which uses resilient foam or springs for biasing and sequencing functions of conventional metal needles.
Needle sheaths for extremely long conventional metal hypodermic needles, mainly for cervical area injections, are shown in U.S. Pat. Nos. 3,356,089 to Francis; and 3,406,687 to Moyer.
No matter what the precise merits of the preceding, cited patents, none anticipates this invention.